I believe this matter is quite complex and there cannot be a unique point of view, of course.
Mine is this. The level progression of this server has always been quite slow, especially for the higher levels, but also for the first levels: I managed to hit level 6 during the NCE but it was circumstantial, since I'm aware in the same time I would have hit probably level 4 if high levels were around. There was more possibilities for RP and there were parties more balanced while dungeoning, this is my opinion.
I've been playing here with occasional interruptions for 8 years by now and I admit when the server was smaller (no Dementlieu, Hazlan, Har-Akir, Sithicus, Blaustein, Perfidius, Wachter's lands, not many dungeons in Village of Barovia etc), there were just a few areas which could grant decent xps for dungeoning, and once you hit some level 14-15 dungeoning became hardly rewarding at all. At that time there were even no crafts, if not smithing, and herbalism was something new (probably around 6-7 years ago), alchemy came even later, magical weapons were rarer. Believe me if you were not there, it was not easy at all to even yearn at lev 20. Yet there were people who managed.
Now the situation is clearly different, many things have changed, and some things are easier: if you don't find a good spawn, you may check the other dozens dungeons for your levels. If you need to lift the cap of your characters, you may commit to one of the exhaustive crafts.
The sense of progression here is mainly related to the stories, there are some who, more favourable in time zones, are more involved than others, but the server is never empty; our biography boards are full with many interesting stories of the players, most of them are things which have happened in game.
However I am with Prophet here, there is also a sense of satisfaction in the mechanical progression, for a series of reasons which have been widely stated already (the need of some skills, feats, etc to shape the character more, for instance), and sometimes some of us (me included) cannot really spend more than a couple of hours daily here, and making things harder would easily spoil part of the fun.
On the other hand there is a matter of attitude, and as an Italian I'm well aware of this. You can find even the most complex algorythm to have a proper balance on progression or whatever, but those who have the proper skills to level up faster will do anyway, while those who are already slow in levelling will be just slower. The attitude, in general, which should be changed is that levelling up is more important than the shared narrative we're all involved in: level progression, in my view, is good as it is, and something more could be done by us players. However I admit some dungeons could be tweaked in terms of reward/danger. I personally do not have any lev 20 in my vault, my max level character is a 19 which I have used extensively for 2-3 years, when I could commit up to 8 hours daily, but I never complained of her being slow: she was part of some of the most fun stories I was ever involved. I was hungry for stories and involvement. Had she been slower, yes, I would have enjoyed the stories as well, but for sure she would have been less "shaped" in the mechanical build (and this doesn't mean anything necessarily related to fighting but also social skills).
In my view things should remain the same, with some tweaking here and there. But however things are done and decided, I fully trust in the Developing team wider vision, and I will, personally, try as usual to be happy with the stories around my characters.